touareg

Trying to sort out a weird hesitation problem that I am having. When lifting off the gas to enter a corner, then pressing the gas, I feel like I have lost power, can press the pedal to the floor and feels like I am in the wrong gear, power slowly builds up.

I replaced my cap/rotor. New wires, new injectors. New FPR.

Only seems to happen after 10 or so minutes from cold.

Where should I start looking? This sounds like an electrical problem, as idle is rock steady and only when car is warm.

Any recommendations of what to hook up to the DME, would durametric logging be good in this case?

I have not used durametric to log things, but I think this may be a good learning experience.

V2Rocket

Check the resistance of the DME temperature sender at the front of the engine (blue plastic connector) and compare it with the values on Clarks-garage.
My guess is cold-start enrichment not working right.

touareg

Thanks, I assume this is what you are talking about? I need to get the correct pinout for the 968 DME.

DME Temperature Sensor Testing
Tools
• Multimeter
• Test Leads
Procedure
1. Turn the ignition switch OFF.
2. Disconnect the DME computer electrical connector.
3. Connect an ohmmeter between terminal 13 on the disconnected DME plug and
ground.
4. Check for the following resistances:
DME Temperature Sensor Resistances
15-30 °C (59-
86 °F)
At 59 °F approximately 3.3
k-ohms
At 86 °F approximately
1.46 k-ohms
5. NOTE
Page 7 of 9
6. The next part of the DME temperature sensor testing assumes that the temperature
gauge on the dash is working properly.
7. Connect the DME plug connector.
8. Start the car and run until the temperature gauge on the dash indicates
approximately 80 °C (see dash temperature gauge section). If you suspect that the
dash gauge is not working properly, you can check the surface temperature on the
block near the DME temperature sensor.
9. Turn the engine OFF.
10. Disconnect the DME computer plug and connect ohmmeter as described in Step
3.
11. Turn the ignition switch back ON (Do Not Attempt to Start Car) and check dash
indication is still reading 80 °C. Alternatively, check the surface temperature on
the block near the DME temperature sensor. Compare resistance to the value in
the table below.
DME Temperature Sensor Resistances
80 °C (176 °F) 280-360 ohms
12. If the resistances don't meet the tolerances listed, the DME Temperature sensor
should be replaced. If the resistances indicate higher than the specs, it will cause a
richer mixture. Lower resistances than the specs will result in a lean mixture.

V2Rocket

yes, that process.
alternatively you could just disconnect the plug at sensor on the engine and measure across its terminals there, the values should be comparable.
(do not unplug the sensor while the engine is running)

Jfrahm

O2 sensor also, although it may throw a code if it's enough out of whack.

touareg

Thanks, I think it was replaced about 4 years ago. This weekend going to check the temp sensor for the DME, that fits the most I think.

gtroth

For me that behavior was due to a faulty AFM.
I chased that one for years. AFM always measured correct, but I basically ran out of things to try.
If you could find a way to borrow a known good AFM, that would be a good.

Jfrahm

Could be, but the 968 uses a MAF. There is a Volvo MAF or Audi MAF that can be substituted, the 968 MAF is pretty unique. My spare which worked fine in the 968 is a Volvo 960 MAF.

Arominus

look for vac leaks, my 68 swapped s2 got pissy at random times due to a loose clamp at the Evap valve. It had a pretty healthy vac leak when the Evan system was trying to pull from the charcoal canister. I found it when replacing the clutch hose and have had no issues since. It was driving me nuts trying to find it before this.

touareg

I hope it is not that, those buggers are expensive at $900, assuming you can find them rebuilt!

Found some part numbers

Cross Interchange Part No. for: BOSCH 0280213017
Downloand
Factory Number Cross Interchange Type Relevance
PORSCHE 95160612501 Direct Cross Interchange 6
BOSCH 0986280139 Direct Cross Interchange 6
VW 034133471N Direct Cross Interchange 6
PORSCHE 95160612502 Direct Cross Interchange 6
AutoZone 0280213017 Direct Cross Interchange 2
CARDONE 7410217 Indirect Cross Interchange 1
PRONTO 7410217 Indirect Cross Interchange 1
PARTS MASTER 7410217 Indirect Cross Interchange 1
AUTOPRIDE 7410217 Indirect Cross Interchange 1
AutoZone 7410217 Indirect Cross Interchange 1

touareg

Do you have a part no? This is a great tip.

As a future spare, I offered 60GBP (~75$ )for one of these, I wonder if I could have got it lower, it was accepted, free shipping from spain.
http://www.ebay.com/itm/Mass-Air-Flo...3D131730112106

thomasmryan

Flip test the MAF and throttle sensor to see if you get close to 4.7V.

It might be worthwhile to pop open the tps and inspect. There might be some blow-by contamination.

Do you have a vacuum gauge or a timing light? The 4 little vacuum elbows can look ok on the outside but plugged internally. A dab of whiteout on the crank pulley might show how much timing advance your getting.


If your probing sensors, the oil temperature sensor in the head oil galley effects the vario engagement rpm.

I bought a new Bosch O2 sensor but it seemed like it switched kinda slow with 40 rpm jumps in a steady state mode. Runs better with the old sensor after cleaning the tip with a propane treatments.

touareg

Thanks, not sure what you mean by the flip test? I have neither of the tools, was going to build a kit for the 968 but my mechanic said he would do it for $60 and found no leaks.

Good tip on the temp sensor in the head, I thought that was only for the gauge on the cluster.

touareg

Searching part numbers on the MAF has lead me to this:

http://12v.org/urs/engine_map/20442.phtml

I guess the flat grill with large openings is to help with air turbulence.

Audi part on left, Porsche special deal on right:



Now this chart shows some measurements from the device, the OEM in this case means the audi part on the left.





I guess dirty pins and bent plug receptacle are common on these too.





Going to co clean my MAF connector now....

thomasmryan

to quote jack white from 'I think ifound the culprit' ;

Two crumbs on my window sill
Two birds sitting there perfectly still
One of them up to no good
The other one doing what he totally should